System and method for controlling capacity of air conditioning coil

ABSTRACT

An air-conditioner unit, is provided comprising: an air-conditioning coil between an input vent and an output vent, receiving return air, passing the return air through the air-conditioning coil, and ejecting supply air, the air-conditioning coil including a plurality of coil paths passing refrigerant; a refrigerant regulator connected to the plurality of coil paths to regulate the flow of the refrigerant through the plurality of coil paths, wherein the refrigerant regulator is configured to have a least two selectable settings, the first selectable setting configuring the refrigerant regulator such that the refrigerant regulator stops refrigerant from flowing through a first subset of the plurality of coil paths and allows refrigerant to flow through a second subset of the plurality of coil paths, the second selectable setting of the refrigerant regulator configuring the refrigerant regulator such that the refrigerant regulator allows refrigerant to flow through all the plurality of coil paths.

FIELD OF THE INVENTION

The disclosed system and method relate generally to air-conditioning units that include an air-conditioning coil that conditions return air to form supply air. More particularly, the disclosed system and method relate to an indoor air-conditioner whose capacity can be controlled and that will provide sufficient cooling and dehumidification during a cooling operation performed at lower than full capacity.

BACKGROUND OF THE INVENTION

During a cooling mode an air-conditioning system will often perform two different operations on the air it is conditioning. First, it will operate to lower the temperature of the air down to a target temperature. Second, it may operate to remove humidity from the air.

These operations are generally both performed by passing air over an air-conditioning coil. Cooled refrigerant is passed through the air-conditioning coil, having a temperature below the air to be cooled. As the air passes over the coil, it transfers heat to the refrigerant in the air-conditioning coil and drops in temperature. In addition, as the air to be cooled passes over the colder air-conditioning coil, water from the air will condense onto the air-conditioning coil and drip into a drain pan below the air-conditioning coil, thus removing moisture from the air and dehumidifying the air.

When an air-conditioner is working at its full capacity, it will cool the refrigerant that passes through its air-conditioning coil to a lowest possible temperature so that it will provide maximum cooling to the air passing through the air-conditioner. An air-conditioner cooling a large area or cooling to a relatively low temperature will typically operate at full capacity (i.e., maximum capacity).

In some situations, however, an air-conditioner will not need to use its entire capacity to achieve the desired level of cooling. For example, the air-conditioner might only need to cool a smaller area than it is capable of cooling or the current temperature in the space to be cooled might not be too high above the air-conditioner's set point.

In such a case, a conventional air-conditioner may either increase the temperature of the refrigerant passing through its air-conditioning coil or operate with reduced refrigerant flow. In either case, this will increase the temperature of the air-conditioning coils and thereby reduce the amount of heat transferred from the air passing over the coils to the refrigerant flowing through the coils. Such an operation will allow the air-conditioning coil to provide an amount of cooling less than the maximum possible amount of cooling that the system can provide. In doing so, the air-conditioner will reduce its operating capacity.

However, as the temperature of the refrigerant in the air-conditioning coil rises or the amount of refrigerant that passes through the air-conditioning coil drops, its ability to withdraw moisture from the air likewise drops. This is because pumping a warmer refrigerant through the air-conditioning coil or pumping a reduced amount of a cooler refrigerant through an air-conditioning coil will cause less moisture to condense on the air-conditioning coil. And if less moisture condenses on the air-conditioning coil, less moisture will be drawn from the air that passes over the air-conditioning coil.

As a result, while a conventional air conditioner will generally be able to remove a desired amount of moisture from air it is cooling when operating at full capacity, such an air conditioner will often fail to provide adequate dehumidification when it operates below its full capacity.

This is an increasing problem as some modern air conditioners are either designed or placed in situation in which they rarely operate at full capacity. As a result, while these modern air conditions adequately cool the areas they are servicing when in a cooling mode, they are inadequate in performing a dehydration operation on that same area when in a cooling mode.

It would therefore be desirable to provide an air-conditioning unit that can both cool an area and adequately dehumidify the area when operating at less than full capacity.

SUMMARY OF THE INVENTION

An air-conditioner unit is provided, comprising: an input vent configured to receive return air; an output vent configured to pass supply air; an air-conditioning coil located between the input vent and the output vent and configured to receive the return air, pass the return air through the air-conditioning coil, and eject the supply air, the air-conditioning coil including a plurality of coil paths configured to pass refrigerant, the plurality of coil paths being configured to accommodate a flow of refrigerant; a refrigerant regulator connected to the plurality of coil paths and configured to regulate the flow of the refrigerant through the plurality of coil paths, wherein the refrigerant regulator is configured to have a least two selectable settings, the first selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator stops refrigerant from flowing through a first subset of the plurality of coil paths and allows refrigerant to flow through a second subset of the plurality of coil paths, the second selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator allows refrigerant to flow through all the plurality of coil paths, the plurality of coil paths in the air-conditioning coil are arranged in parallel with respect to a flow of return air through the air-conditioning coil such that any portion of return air will pass over only one of the plurality of coil paths as the return air flows through the air-conditioning coil from the input vent to the output vent.

The refrigerant regulator may further comprise a valve configured to selectively allow or stop refrigerant from flowing through the first subset of the coil paths.

The valve may be located on a side of the air-conditioning coil that is upstream of the refrigerant flow through the coil paths during a heating mode and is downstream of the refrigerant flow through the coil paths during a cooling mode.

The valve may be located on a side of the air-conditioning coil that is downstream of the refrigerant flow through the coil paths during a heating mode and is upstream of the refrigerant flow through the coil paths during a cooling mode.

The refrigerant regulator may further comprise a plurality of valves configured to selectively allow or stop refrigerant from flowing through the first subset of the coil paths, respectively, and each of the coil paths in the first subset of coil paths may be associated with one of the plurality of valves.

The plurality of valves may be located on a side of the air-conditioning coil that is upstream of the refrigerant flow through the plurality of coil paths during a heating mode and is downstream of the refrigerant flow through the plurality of coil paths during a cooling mode.

The plurality of valves may be located on a side of the air-conditioning coil that is downstream of the refrigerant flow through the plurality of coil paths during a heating mode and is upstream of the refrigerant flow through the plurality of coil paths during a cooling mode.

A first subset of the plurality of valves may be located on a side of the air-conditioning coil that is downstream of the refrigerant flow through the plurality of coil paths during a heating mode and is upstream of the refrigerant flow through the plurality of coil paths during a cooling mode, and a second subset of the plurality of valves may located on a side of the air-conditioning coil that is upstream of the refrigerant flow through the plurality of coil paths during a heating mode and is downstream of the refrigerant flow through the plurality of coil paths during a cooling mode.

An air-conditioner unit is provided, comprising: an input vent configured to receive return air; an output vent configured to pass supply air; an air-conditioning coil located between the input vent and the output vent and configured to receive the return air and eject the supply air, the air-conditioning coil including N separate coil paths configured to pass refrigerant, the N coil paths each having a first port and a second port; N first refrigerant lines corresponding to the N coil paths, each of the N first refrigerant lines being connected to the first port on a corresponding one of the N coil paths and being configured to pass refrigerant to or from the corresponding coil path; N second refrigerant lines corresponding to the N coil paths, each of the N second refrigerant lines being connected to a second port on a corresponding one of the N coil paths and being configured to pass the refrigerant to or from the corresponding coil path; and a refrigerant regulator connected to the N coil paths and configured to regulate the flow of the refrigerant through the N coil paths, wherein the refrigerant regulator is configured to have a least two selectable settings, the first selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator stops refrigerant from flowing through M first coil paths of the N coil paths and allows refrigerant to flow through P second coil paths of the N coil paths, the second selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator allows refrigerant to flow through all N coil paths, the air-conditioning coil is configured such that the return air will pass into the air-conditioning coil from the input vent, exchange heat with one of the N coil paths, and be ejected from the air-conditioning coil as the supply air, the N coil paths in the air-conditioning coil are arranged in parallel with respect to a flow of return air through the air-conditioning coil such that any portion of return air will pass over only one of the N coil paths as the return air flows through the air-conditioning coil from the input vent to the output vent, N is an integer greater than 1, M is an integer greater than 0, P=N−M, and M<N.

The air-conditioner unit may further comprise: a third refrigerant line configured to receive refrigerant from the N second refrigerant lines, wherein the N second refrigerant lines are connected to the third refrigerant line at N connection points, respectively, the refrigerant regulator further comprises a valve located in the third refrigerant line between M first connection points selected from the N connection points and P second connection points selected from the N connection points, and the valve is configured to selectively allow or stop refrigerant from flowing through the M first coil paths.

The valve may include a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output opening to the input opening, and the one-way valve is oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.

The valve may be one of a bi-flow directional solenoid valve, a solenoid and check valve, a linear expansion valve, and a direct-acting solenoid valve.

The air-conditioner unit may further comprise: a third refrigerant line configured to receive refrigerant from the N second refrigerant lines, wherein the N second refrigerant lines are connected to the third refrigerant line at N connection points, respectively, and the refrigerant regulator further comprises M valves located in M second refrigerant lines, respectively, of the N second refrigerant lines between corresponding M first coil paths in the N coil paths and corresponding M first connection points of the N connection points, the M valves being configured to selectively allow or stop refrigerant from flowing through the M first coil paths, respectively.

The M valves may each be one of a bi-flow directional solenoid valve, a solenoid and check valve, a linear expansion valve, and a direct-acting solenoid valve.

The M valves may each include a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; and a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output opening to the input opening, and the one-way valve may be oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.

The air-conditioner unit may further comprise: a refrigerant distributor having a first refrigerant path on a first end and N second refrigerant paths on a second end, wherein the N first refrigerant lines are connected to the N second refrigerant paths, respectively, and the refrigerant regulator further comprises M valves located in M first refrigerant lines, respectively, of the N first refrigerant lines between corresponding M first coil paths in the N coil paths and the corresponding M second refrigerant paths of the N second refrigerant paths, the M valves being configured to selectively allow or stop refrigerant from flowing through the M first coil paths, respectively.

The M valves may each be one of a bi-flow directional solenoid valve, a solenoid and check valve, a linear expansion valve, and a direct-acting solenoid valve.

The M valves may each include a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; and a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output port to the input port, and the one-way valve may be oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.

The air-conditioner unit may further comprise: a first refrigerant distributor configured to pass the refrigerant and having a first refrigerant path on a first end and M second refrigerant paths on a second end; a first expansion valve connected to the first refrigerant path and configured to controllably restrict a first flow of refrigerant through the first refrigerant path; a second refrigerant distributor configured to pass the refrigerant and having a third refrigerant path on a first end and P fourth refrigerant paths on a second end; and a second expansion valve connected to the third refrigerant path and configured to controllably restrict a second flow of refrigerant through the third refrigerant path, wherein M controllable first refrigerant lines selected from the N first refrigerant lines are connected to the M second refrigerant paths in the first refrigerant distributor, respectively, P non-controllable first refrigerant lines selected from the N first refrigerant lines are connected to the P fourth refrigerant paths in the second refrigerant distributor, respectively, and the refrigerant regulator comprises the first and second expansion valves.

The air-conditioner unit may further comprise: a refrigerant distributor configured to pass the refrigerant and having a first refrigerant path on a first end and N second refrigerant paths on a second end; an expansion valve connected to the first refrigerant path and configured to controllably restrict a flow of refrigerant through the first refrigerant path, wherein the N first refrigerant lines are connected to the N second refrigerant paths, respectively.

A method of operating an air-conditioner in a cooling mode is provided, the air-conditioner having an air-conditioning coil, the air-conditioning coil having N parallel coil paths, the method comprising: stopping refrigerant flow through M first coil paths selected from the N parallel coil paths; distributing refrigerant through P second coil paths selected from the N parallel coil paths; receiving return air at the air-conditioning coil; passing M first portions of the return air through the air-conditioning coil past the M first coil paths as M unconditioned portions of supply air, respectively; passing P second portions of the return air through the air-conditioning coil past the P second coil paths as P conditioned portions of supply air, respectively; cooling the P second portions of the return air by exchanging heat between the P second portions of the return air and the refrigerant distributed through the P second coil paths, respectively, to generate the P conditioned portions of supply air; and combining the M unconditioned portions of supply air and the P conditioned portions of supply air to form combined supply air, wherein each of the M first portions of return air and each of the P second portions of the return air flow past only one of the N parallel coil paths, N is an integer greater than 1, M is an integer greater than 0, P=N−M, and M<N.

The operation of stopping refrigerant flow through the M first coil paths may further include operating a single valve to stop the flow of refrigerant through the M first coil paths.

The single valve may stop the flow of refrigerant to the M first coil paths by blocking the flow of refrigerant flowing into the M first coil paths.

The single valve may stop the flow of refrigerant to the M first coil paths by blocking the flow of refrigerant flowing out of the M first coil paths.

The operation of stopping refrigerant flow through the M first coil paths may further include operating M valves to stop the flow of refrigerant through the M first coil paths, respectively, and M may be an integer greater than 1.

The M valves may stop the flow of refrigerant to the M first coil paths by blocking the flow of refrigerant flowing into the M first coil paths, respectively.

The M valves may stop the flow of refrigerant to the M first coil paths by blocking the flow of refrigerant flowing out of the M first coil paths, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures where like reference numerals refer to identical or functionally similar elements and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate an exemplary embodiment and to explain various principles and advantages in accordance with the present disclosure.

FIG. 1 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to first disclosed embodiments;

FIG. 2 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to second disclosed embodiments;

FIG. 3 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to third disclosed embodiments;

FIG. 4 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to fourth disclosed embodiments;

FIG. 5 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to fifth disclosed embodiments;

FIG. 6 is a diagram of an indoor air-conditioning unit having an air-conditioning coil whose capacity can be controlled according to sixth disclosed embodiments;

FIGS. 7A-7C are diagrams of a valve used in the embodiments of FIGS. 1-5 according to disclosed embodiments;

FIGS. 8A-8C are diagrams of a valve used in the embodiments of FIGS. 1-5 according to alternate disclosed embodiments; and

FIG. 9 is a flow chart of a cooling operation of an air-conditioning unit having an air-conditioning coil whose capacity can be varied according to disclosed embodiments.

DETAILED DESCRIPTION

The instant disclosure is provided to further explain in an enabling fashion the best modes of performing one or more embodiments of the present invention. The disclosure is further offered to enhance an understanding and appreciation for the inventive principles and advantages thereof, rather than to limit in any manner the invention. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.

It is further understood that the use of relational terms such as first and second, and the like, if any, are used solely to distinguish one from another entity, item, or action without necessarily requiring or implying any actual such relationship or order between such entities, items or actions. It is noted that some embodiments may include a plurality of processes or steps, which can be performed in any order, unless expressly and necessarily limited to a particular order; i.e., processes or steps that are not so limited may be performed in any order.

Air-Conditioning Unit Having a Variable Capacity Air-Conditioning Coil

FIG. 1 is a diagram of an air-conditioning unit 100 having an air-conditioning coil 105 whose capacity can be controlled according to first disclosed embodiments.

As shown in FIG. 1, the air-conditioning unit 100 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a refrigerant distributor 120, an expansion valve 125, a refrigerant flow pipe 130, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, a plurality of nodes 160A-160D, and a valve 170. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105. The air-conditioning unit 100 may be an indoor air-conditioning unit.

The air-conditioning coil 105 includes a collection of hollow tubes for circulating refrigerant. The refrigerant passing through the air-conditioning coil 105 will be heated to a temperature greater than ambient temperature during a heating operation (i.e., a heating mode) and will be cooled to a temperature below ambient temperature during a cooling operation (i.e., a cooling mode).

During a cooling operation the cooled refrigerant will pass through the air-conditioning coil 105 in a first direction, entering the air-conditioning coil 105 in first openings on a first side and exiting the air-conditioning coil 105 from second openings on a second side. During a heating operation the heated refrigerant will pass through the air-conditioning coil 105 in the opposite direction, entering the air-conditioning coil 105 in the second openings on the second side and exiting the air-conditioning coil 105 from the first openings on the first side.

The input vent 110 is an air vent that draws in return air, typically from the zone that the air-conditioning unit 100 services. This zone can be a room in a building, multiple rooms in a building, or any other area whose air needs to be heated or cooled. The input vent 110 is located upstream from the air-conditioning coil 105 with respect to the path of air that passes through the air-conditioning unit 100.

The output vent 115 is located downstream from the air-conditioning coil 105 with respect to the path of air that passes through the air-conditioning unit 100. The output vent 115 receives air from the air-conditioning coil 105 that it provides to the zone assigned to the air-conditioning unit 100 as supply air. The air the output vent 115 receives can be conditioned return air that has been heated or cooled, unconditioned return air that has been neither heater nor cooled, or a combination of conditioned and unconditioned return air. The output vent 115 can also be called an exhaust vent.

The refrigerant distributor 120 is a mechanism provided to pass refrigerant between a single opening on a first side and a plurality of openings on a second side. For example, in the exemplary embodiment of Applicant's FIG. 1, the refrigerant distributor 120 operates to pass refrigerant between a single opening on a first side and four openings on a second side. The single opening on the first side is connected to the expansion valve 125, while the plurality of openings on the second side are connected to the plurality of first refrigerant lines 140A-140D, respectively.

The expansion valve 125 is a valve that controls the amount of refrigerant provided to the air-condition coil 105 via the first refrigerant lines 140A-140D during a cooling mode. It is connected between the first refrigerant flow pipe 130 and the refrigerant distributor 120.

The refrigerant flow pipe 130 is a pipe that allows refrigerant to flow to and from the expansion valve 125 with respect to the remainder of the air-conditioning system not shown in FIG. 1. The first refrigerant flow pipe 130 is connected between the expansion valve 125 and the remainder of the air-conditioning system 100 that is not shown in FIG. 1.

The plurality of first refrigerant lines 140A-140D are tubes or pipes that facilitate the movement of refrigerant between the refrigerant distributor 120 and the plurality of coil paths 180 in the air-conditioning coil 105. Each first refrigerant line 140 is connected between one of the plurality of openings on the second side of the refrigerant distributor 120 and a corresponding one of the plurality of coil paths 180. In this way, each of the plurality of coil paths 180 will be connected to the refrigerant distributor 120 by a corresponding first refrigerant line 140. For ease of disclosure, the plurality of first refrigerant lines 140A-140D may be referred to, individually or collectively, as first refrigerant lines 140.

The plurality of second refrigerant lines 150A-150D are pipes that facilitate the movement of refrigerant between the third refrigerant line 155 and the plurality of coil paths 180 in the air-conditioning coil 105. Each second refrigerant line 150 is connected between the third refrigerant line 155 and a corresponding one of the plurality of coil paths 180. In this way, each of the plurality of coil paths 180 will be connected to the third refrigerant line 155 by a corresponding second refrigerant line 150. For ease of disclosure, the plurality of second refrigerant lines 150A-150D may be referred to, individually or collectively, as second refrigerant lines 150.

The third refrigerant line 155 passes refrigerant to and from the second refrigerant lines 150 with respect to the remainder of the air-conditioning system 100 not shown in FIG. 1. The third refrigerant line 155 is connected between the second refrigerant lines 150 and the remainder of the air-conditioning system 100 not shown in FIG. 1.

The plurality of nodes 160A-160D represent the connection points between the second refrigerant lines 150 and the third refrigerant line 155, respectively. For example, in the embodiment of FIG. 1, the first node 160A could be an L-joint fitting, while the second through fourth nodes 160B-160D could be T-joint fittings. However, this is by way of example only. Any acceptable way of connecting the second refrigerant lines 150 to the third refrigerant line 155 could be used as a node 160. For ease of disclosure, the plurality of nodes 160A-160D may be referred to, individually or collectively, as nodes 160.

The valve 170 is located on the third refrigerant line 155 between two of the nodes 160. The valve 170 is designed such that it always passes refrigerant in a direction that the refrigerant flows during a heating mode and may selectively stop the flow of refrigerant in the direction the refrigerant flows during a cooling mode. The valve 170 can be a bi-flow directional solenoid valves, a combined solenoid valve and check valve, a linear expansion valve, a direct-acting solenoid valve, or any other suitable valve.

The valve 170 has at least two settings. A first setting allows refrigerant to flow freely through the valve 170 in both directions. This corresponds to the air-conditioning coil 105 operating at full capacity. A second setting allows refrigerant to freely flow through the valve 170 in a direction that refrigerant flows during a heating mode but stops the flow of refrigerant in the direction that the refrigerant flows during a cooling mode. This corresponds to the air-conditioning coil 105 operating at reduced capacity. The valve 170 is controllable by control signals received from an air-conditioner controller (not shown).

The valve 170 can therefore selectively block the flow of cooled refrigerant into the second refrigerant lines 150 and coil paths 180 upstream of the valve 170 during a cooling mode. In doing so, the valve 170 can selectively turn the coil paths 180 upstream of the valve 170 on and off during a cooling mode, thus selecting between a cooling mode at full capacity and a cooling mode at reduced capacity.

In the embodiment of FIG. 1, the valve 170 is located between the second node 160B and the third node 160C and so can selectively stop the flow of cooled refrigerant into two coil paths 180A and 180B selected from four total coil paths 180A-180D. However, this is by way of example only. Alternate embodiments can employ more or fewer coil paths 180. Furthermore, the valve 170 may be placed at any location on the third refrigerant line 155 that is between two nodes 160, allowing it to control the flow of cooled refrigerant into a different subset of the coil paths 180. All that is required is that in the reduced-capacity cooling mode at least one node 160 is on a first side of the valve 170 meaning that at least one coil path 180 has the flow of refrigerant prevented from passing through it, and at least one node 160 is on a second side of the valve 170 meaning that at least one coil path 180 has the flow of refrigerant unrestricted from passing through it.

The plurality of coil paths 180A-180D are individual sets of tubing that pass refrigerant through them from a first side to a second side. Collectively the plurality of coil paths 180 make up the air-conditioning coil 105. The refrigerant passing through the coil paths 180 will be heated to a temperature above ambient temperature during a heating mode and will be cooled to a temperature below ambient temperature during a cooling mode. For ease of disclosure, the plurality of coil paths 180A-180D may be referred to, individually or collectively, as coil paths 180.

The coil paths 180 are arranged in parallel with respect to the flow of air through the air-conditioning coil 105. In other words, return air passing through the air-conditioning coil 105 will only pass over one of the coil paths 180 before being expelled as supply air. Return air passing through the air-conditioning coil 105 will never pass over more than one coil path 180.

Each coil path 180 has two openings for passing refrigerant. A first opening on a first side of the coil path 180 is connected to a respective first refrigerant line 140, while a second opening on a second side of the coil path 180 is connected to a respective second refrigerant line 150.

The air-conditioning unit 100 can operate in at least three different modes: a heating mode, a cooling mode at full capacity, and a cooling mode at reduced capacity. The air-conditioning unit 100 will choose between a heating mode and a cooling mode using conventional air-conditioner elements not shown in FIG. 1. When in a cooling mode, the air-conditioning unit 100 will determine whether it operates at full capacity or reduced capacity based on the configuration of the valve 170. When the valve 170 allows refrigerant to pass through it in a cooling mode, the air-conditioning unit 100 will operate at full capacity; and when the valve 170 stops refrigerant flow through it in a cooling mode, the air-conditioning unit 100 will operate at reduced capacity.

In all three of these possible modes, refrigerant flows through one or more of the coil paths 180 to or from the first, second, and third refrigerant lines 140, 150, 155. This refrigerant will be heated above the ambient temperature in the zone to be heated during a heating mode and will be cooled below the ambient temperature in the zone to be cooled during a cooling mode. Return air will be drawn into the input vent 110 and will be passed through the air-conditioning coil 105 where it will exchange heat with the refrigerant passing through the air-conditioning coil 105, heating or cooling the return air as appropriate. The heated or cooled return air will then exit the air-conditioning coil 105 into the output vent 115 as supply air. The supply air will then be provided to the zone that the air-conditioning unit 100 services.

During a heating mode, heated refrigerant will be provided to the third refrigerant line 155, which will distribute the heated refrigerant to the second refrigerant lines 150, respectively. The valve 170 is configured to allow heated refrigerant to continually flow through it when it is flowing in a heating mode. The refrigerant will pass from the third refrigerant line 155 through each of the second refrigerant lines 150 into respective coil paths 180 where it will exchange heat with the return air passing through the air-conditioning coil 105. This heat exchange operation will heat the return air and cool the refrigerant. The heated return air will pass to the output vent 115 as heated supply air, while the cooled refrigerant will pass from the respective coil paths 180 to respective first refrigerant lines 140, and there through the refrigerant distributor 120, the expansion valve 125, and the refrigerant flow pipe 130. From the refrigerant flow pipe 130 the cooled refrigerant will pass through the remainder of the air-conditioning unit 100, where it will be reheated and provided again to the third refrigerant line 155 as heated refrigerant.

During a full-capacity cooling mode, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, which will control the amount of refrigerant it passes and the temperature of the refrigerant, as appropriate. Cooled refrigerant will then be passed from the expansion valve 125 to the single opening on the first side of the refrigerant distributor 120. The refrigerant distributor will then distribute the cooled refrigerant to each of the plurality of first refrigerant lines 140 at the corresponding plurality of openings on the second side of the refrigerant distributor 120.

The cooled refrigerant will pass through each of the first refrigerant lines 140 into openings at first ends of each of the corresponding coil paths 180 and will fill the corresponding coil paths 180 with cooled refrigerant. The cooled refrigerant will then pass through the coil paths 180 and will fill corresponding second refrigerant lines 150.

In the full-capacity cooling mode, the valve 170 will be set such that the cooled refrigerant can freely flow through it. As a result, cooled refrigerant will pass from all the second refrigerant lines 150 to the third refrigerant line 155 and on to the remainder of the air-conditioning unit 100. In this way, all the coil paths 180 will have cooled refrigerant circulating through them. As a result, air passing over all the coil paths 180 will exchange heat with the refrigerant flowing through the coil paths 180, thus cooling the air.

This heat exchange operation will cool the return air and heat the refrigerant. The cooled return air will pass to the output vent 115 as cooled supply air, while the heated refrigerant from all the coil paths 180 will pass from the coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 100, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

The cooled refrigerant will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through a coil path 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each of the coil paths 180 will be both cooled and dehumidified.

In the reduced-capacity cooling mode, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, the refrigerant distributor 120, the plurality of first refrigerant lines 140, the plurality of coil paths 180, and the plurality of second refrigerant lines 150 as described above with respect to the full-capacity cooling mode. However, during the reduced-capacity cooling mode, the valve 170 will be configured such that the cooled refrigerant cannot flow through it. Because the valve 170 is located on the third refrigerant line 155 upstream of the third and fourth nodes 160C, 160D, cooled refrigerant will pass from the second refrigerant lines 150C, 150D to the third refrigerant line 155 and on to the remainder of the air-conditioning unit 100 without interference. But, because the valve 170 will not pass cooled refrigerant and is located downstream of the first and second nodes 160A, 160B, the cooled refrigerant from second refrigerant lines 150A and 150B will fill up the portion of the third refrigerant line 155 upstream of the valve 170 but will not pass through the portion of the refrigerant line 155 downstream of the valve 170 and on to the remainder of the air-conditioning system not shown in FIG. 1.

The refrigerant that initially fills the first and second coil paths 180A, 180B will briefly cool the air passing over them. However, with no circulation, the refrigerant will soon rise to ambient temperature and will cease to cool the return air passing over the first and second coil paths. 180A, 180B. During the reduced-capacity cooling operation, only air passing over the third and fourth coil paths 180C, 180D will be cooled and dehumidified. Air passing over the first and second coil paths 180A, 180B will be neither cooled nor dehumidified.

However, while the first and second coil paths 180A, 180B will pass unconditioned return air that is neither cooled nor dehumidified, the third and fourth coil paths 180C, 180D will pass conditioned return air that has been both cooled and dehumidified. Since the return air from all the coil paths 180 is combined to form the supply air, the resulting supply air will still be both cooler and less humid than the return air provided to the plurality of coil paths 180. Thus, despite performing its cooling at a lower capacity in fewer than all the coil paths 180, the air-conditioning unit 105 will still act to both cool the return air that passes through it and remove moisture from the return air it cools.

The heat exchange operation performed during the reduced-capacity cooling mode will cool a portion of the return air and heat the refrigerant. The cooled return air will pass to the output vent 115 and combine with uncooled return air to form cooled supply air, while the heated refrigerant from all of the third and fourth coil paths 180C, 180D will pass from the third and fourth coil paths 180C, 180D to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 100, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

As with the full-capacity cooling mode, the cooled refrigerant in the reduced-capacity cooling mode will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through one of the third or fourth coil paths 180C, 180D, moisture will condense from the passing return air onto the coil path 180C, 180D. As a result, air passing over each of the coil paths 180C, 180D will be both cooled and dehumidified.

The full-capacity cooling mode is referred to as being at “full capacity” since all the coil paths 180 operate to cool and dehumidify the return air. The reduced-capacity cooling mode is referred to as being at “reduced capacity” because fewer than all the coil paths 180 operate to cool and dehumidify the return air.

The air-conditioning coil 105 will operate to remove moisture from the return air in both the full-capacity cooling mode and the reduced-capacity cooling mode because the refrigerant supplied to the air-conditioning coil 105 will be at a temperature in both cooling modes that is low enough to condense moisture from air passing over coil paths 180 containing the cooled refrigerant. In other words, the air-conditioning unit 100 will provide enough cooling to the refrigerant for dehumidification whether the air-conditioning unit is operating at full capacity or reduced capacity. Because the cooled refrigerant will be at a sufficiently low temperature for dehumidification, it will be cold enough to cause moisture to condense from the return air as the return air passes over any of the coil paths 180 in which cooled refrigerant is circulating, whether it is all the coil paths 180 in full capacity operation or only some of the coil paths 180C, 180D in reduced capacity operation.

The reduced capacity of the air-conditioning coil is set based on how many coil paths 180 may be restricted by the operation of the valve 170. For example, in the exemplary embodiment shown by FIG. 1, the first and second coil paths 180A, 180B can have flow of refrigerant through them restricted by the operation of the valve 170, and third and fourth coil paths 180C, 180D pass refrigerant regardless of the configuration of the valve 170. Thus, the valve can restrict 50% of the coil paths 180 from receiving refrigerant. If the coil paths 180 are all the same size, that means that the reduced capacity operation will be at 50% of the maximum capacity. If the coil paths 180 are different sizes, the reduced capacity will depend upon the percentage of total refrigerant flow that can be restricted by the valve 170.

Alternate embodiments can alter the number of coil paths 180, the sizes of the various coil paths 180, and the placement of the valve 170 to provide a desired reduced capacity percentage.

Second Disclosed Embodiment

FIG. 2 is a diagram of an air-conditioning unit 200 having an air-conditioning coil 105 whose capacity can be controlled according to second disclosed embodiments.

As shown in FIG. 2, the air-conditioning unit 200 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a refrigerant distributor 120, an expansion valve 125, a refrigerant flow pipe 130, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, a plurality of nodes 160A-160D, and a plurality of valves 270A, 270B. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105.

The air-conditioning coil 105, the input vent 110, the output vent 115, the refrigerant distributor 120, the expansion valve 125, the refrigerant flow pipe 130, the plurality of first refrigerant lines 140A-140D, the plurality of second refrigerant lines 150A-150D, the third refrigerant line 155, the plurality of nodes 160A-160D, and the plurality of coil paths 180A-180D operate essentially as described above with respect to the embodiment of FIG. 1. As a result, a description of these elements with similar reference numbers will not be repeated. Unlike the embodiment of FIG. 1, no valve 170 is provided on the third refrigerant line 155 in the embodiments of FIG. 2.

The plurality of valves 270A and 270B are provided on the second refrigerant lines 150A and 150B, respectively. The valves 270 are each designed such that they always pass refrigerant in a direction that the refrigerant flows during a heating mode and may selectively stop the flow of refrigerant in the direction the refrigerant flows during a cooling mode. The valves 270 can be bi-flow directional solenoid valves, a combined solenoid valve and check valve, a linear expansion valve, a direct-acting solenoid valve, a different kind of suitable valve, or a combination of these types of valves. The valves 270 are controllable by control signals received from an air-conditioner controller (not shown).

The valves 270 each have at least two settings. A first setting allows refrigerant to flow freely through the valve 270 in both directions. This corresponds to the air-conditioning coil 105 operating at full capacity. A second setting allows refrigerant to freely flow through the valve 270 in a direction that refrigerant flows during a heating mode but restricts the flow of refrigerant in the direction that the refrigerant flows during a cooling mode. This corresponds to the air-conditioning coil 105 operating at reduced capacity.

Each valve 270 can therefore selectively block the flow of cooled refrigerant through the second refrigerant line 150 it is located on and therefore through the corresponding coil path 180 connected to that second refrigerant line 150 during a cooling mode. In doing so, the valve 270 can selectively turn on and off the coil paths 180 connected to the second refrigerant line the valve 270 is located on during a cooling mode, thus selecting between a cooling mode at full capacity and one or more cooling modes at reduced capacity.

In the embodiment of FIG. 2, the valves 270 are located on the second refrigerant lines 150A and 150B and so can selectively stop the flow of cooled refrigerant into first and second coil paths 180A and 180B selected from four total coil paths 180A-180D. However, this is by way of example only. Alternate embodiments can employ more or fewer coil paths 180. Furthermore, valves 270 may be placed at more or fewer second refrigerant lines 150, allowing them to control the flow of cooled refrigerant into a different subset of the coil paths 180.

In operation, the air-conditioning unit 200 can operate in at least three different modes: a heating mode, a cooling mode at full capacity, and at least one cooling mode at reduced capacity. The air-conditioning unit 200 will choose between a heating mode and a cooling mode using conventional air-conditioner elements not shown in FIG. 2. When in a cooling mode, the air-conditioning unit 200 will determine whether it operates at full capacity or reduced capacity based on the configuration of the valves 270. When all the valves 270 allow refrigerant to pass through them in a cooling mode, the air-conditioning unit 200 will operate at full capacity; and when at least one valve 270 restricts refrigerant flow through it in a cooling mode, the air-conditioning unit 200 will operate at reduced capacity.

Furthermore, if each valve 270 is operable independent of the other valves 270, multiple reduced-capacity cooling modes can be provided by varying which valves 270 allow refrigerant to pass through them and which valves 270 stop refrigerant passing through them. For example, in the embodiment of FIG. 2, a first reduced-capacity cooling mode can correspond to both valves 270 restricting refrigerant passing through them in a cooling mode, and a second reduced-capacity cooling mode can correspond to one valve 270 allowing refrigerant to pass through it in a cooling mode and one valve 270 restricting refrigerant from passing through it in a cooling mode.

Furthermore, if the coil paths 180 corresponding to the valves 270 are of different sizes, the air-conditioning unit 200 can have three reduced-capacity cooling modes. A first reduced-capacity cooling mode can correspond to both valves 270A, 270B restricting refrigerant passing through them in a cooling mode, a second reduced-capacity cooling mode can correspond to valve 270A allowing refrigerant to pass through it in a cooling mode and valve 270B restricting refrigerant from passing through it in a cooling mode, and a third reduced-capacity cooling mode can correspond to valve 270B allowing refrigerant to pass through it in a cooling mode and valve 270A restricting refrigerant from passing through it in a cooling mode.

In all these possible modes, refrigerant flows through one or more of the coil paths 180 to or from the first, second, and third refrigerant lines 140, 150, 155. This refrigerant will be heated above the ambient temperature in the zone to be heated during a heating mode and will be cooled below the ambient temperature in the zone to be cooled during a cooling mode. Return air will be drawn into the input vent 110 and will be passed through the air-conditioning coil 105 where it will exchange heat with the refrigerant passing through the air-conditioning coil 105, heating or cooling the return air as appropriate. The heated or cooled return air will then exit the air-conditioning coil 105 into the output vent 115 as supply air. The supply air will then be provided to the zone that the air-conditioning unit 200 services.

During a heating mode, heated refrigerant will be provided to the third refrigerant line 155, which will distribute the heated refrigerant to the second refrigerant lines 150, respectively. The valves 270 are each configured to allow heated refrigerant to continually flow through them when it is flowing in a heating mode. The refrigerant will therefore pass from the third refrigerant line 155 through each of the second refrigerant lines 150 into respective coil paths 180 where it will exchange heat with the return air passing through the air-conditioning coil 105. This heat exchange operation will heat the return air and cool the refrigerant. The heated return air will pass to the output vent 115 as heated supply air, while the cooled refrigerant will pass from the respective coil paths 180 to respective first refrigerant lines 140, and there through the refrigerant distributor 120, the expansion valve 125, and the refrigerant flow pipe 130. From the refrigerant flow pipe 130 the cooled refrigerant will pass through the remainder of the air-conditioning unit 200, where it will be reheated and provided again to the third refrigerant line 155 as heated refrigerant.

During a full-capacity cooling mode, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, which will control the amount of refrigerant it passes, as appropriate. Cooled refrigerant will then be passed from the expansion valve 125 to the single opening on the first side of the refrigerant distributor 120. The refrigerant distributor will then distribute the cooled refrigerant to each of the plurality of first refrigerant lines 140 at the corresponding plurality of openings on the second side of the refrigerant distributor 120.

The cooled refrigerant will pass through each of the first refrigerant lines 140 into openings at first ends of each of the corresponding coil paths 180 and will fill the corresponding coil paths 180 with cooled refrigerant. The cooled refrigerant will then pass through the coil paths 180 and will fill corresponding second refrigerant lines 150.

In the full-capacity cooling mode, the valves 270 will all be set such that the cooled refrigerant can freely flow through them. As a result, cooled refrigerant will pass from all the second refrigerant lines 150 to the third refrigerant line 155 and on to the remainder of the air-conditioning unit 200. In this way, all the coil paths 180 will have cooled refrigerant circulating through them. As a result, air passing over all the coil paths 180 will exchange heat with the refrigerant flowing through the coil paths 180, thus cooling the air.

This heat exchange operation will cool the return air and heat the refrigerant. The cooled return air will pass to the output vent 115 as cooled supply air, while the heated refrigerant from all the coil paths 180 will pass from the coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 200, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

The cooled refrigerant will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through a coil path 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each of the coil paths 180 will be both cooled and dehumidified.

In the one or more reduced-capacity cooling modes, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, the refrigerant distributor 120, the plurality of first refrigerant lines 140, the plurality of coil paths 180, and the plurality of second refrigerant lines 150 as described above with respect to the full-capacity cooling mode. However, during the reduced-capacity cooling mode, at least one valve 270 will be configured such that the cooled refrigerant cannot flow through it in a direction the refrigerant flows during the cooling mode.

For coil paths 180C, 180D whose associated second refrigerant line 150C, 150D do not have a valve 270, cooled refrigerant will pass from coil paths 180C, through the second refrigerant lines 150C, 150D to the third refrigerant line 155 and on to the remainder of the air-conditioning unit 200 without interference. For coil paths 180 whose associated second refrigerant line 150 have a valve 270, but whose valves are set to permit the flow of cooled refrigerant during the cooling mode, the cooled refrigerant will pass from the coil path 180, through corresponding second refrigerant line 150 to the third refrigerant line 155 and on to the remainder of the air-conditioning unit 200 without interference. However, for coil paths 180 whose associated second refrigerant line 150 have a valve 270, but whose valve is set to restrict the flow of cooled refrigerant during the cooling mode, the cooled refrigerant from associated coil paths 180 will fill up the portion of the second refrigerant line 150 upstream of the valve 270 but will not pass through the portion of the second refrigerant line 150 downstream of the valve 270 and on to the remainder of the air-conditioning system 200 not shown in FIG. 2.

The refrigerant that initially fills corresponding coil path 180 will briefly cool the air passing over them. However, with no circulation, the refrigerant will soon rise to ambient temperature and will cease to cool the return air passing over the corresponding coil path 180. During a reduced-capacity cooling operation, only air passing over coil paths 180 that have refrigerant flowing through them will be cooled and dehumidified. Air passing over coil path 180 that does not have refrigerant flowing through it will be neither cooled nor humidified.

However, while one or more coil paths 180 will pass unconditioned return air that is neither cooled nor dehumidified, one or more coil paths 180 will pass conditioned return air that has been both cooled and dehumidified. Since the return air from all the coil paths 180 is combined to form the supply air, the resulting supply air will still be both cooler and less humid than the return air provided to the plurality of coil paths 180. Thus, despite performing its cooling at a lower capacity in fewer than all the coil paths 180, the air-conditioning unit 200 will still act to both cool the return air that passes through it and remove moisture from the return air it cools.

The heat exchange operation performed during a reduced-capacity cooling mode will cool a portion of the return air and heat the refrigerant. The cooled return air will pass to the output vent 115, combined with uncooled return air to form cooled supply air, while the heated refrigerant from all coil paths 180 it circulates through will pass from coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 200, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

As in the full-capacity cooling mode, the cooled refrigerant in the reduced-capacity cooling mode will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through one or more coil paths 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each coil path 180 that has refrigerant flowing through it will be both cooled and dehumidified.

The full-capacity cooling mode is referred to as being at “full capacity” since all the coil paths 180 operate to cool and dehumidify the return air. The reduced-capacity cooling mode is referred to as being at “reduced capacity” because fewer than all the coil paths 180 operate to cool and dehumidify the return air.

The air-conditioning coil 105 will therefore remove moisture from the return air in both the full-capacity cooling mode and any reduced-capacity cooling mode because the refrigerant supplied to the air-conditioning coil 105 will be at a temperature in both cooling modes that is low enough to condense moisture from air passing over coil paths 180 containing the cooled refrigerant. In other words, the air-conditioning unit 200 will provide enough cooling to the refrigerant for dehumidification whether the air-conditioning unit 200 is operating at full capacity or reduced capacity. Because the cooled refrigerant will be at a sufficiently low temperature for dehumidification, it will be cold enough to cause moisture to condense from the return air as the return air passes over any of the coil paths 180 in which cooled refrigerant is circulating, whether it is all the coil paths 180 in full capacity operation or only some of the coil paths 180 in reduced capacity operation.

The reduced capacity of the air-conditioning coil is set based on which coil paths 180 are be restricted by the operation of the valves 270. For example, in the exemplary embodiment shown by FIG. 2, the first and second coil paths 180A, 180B can have flow of refrigerant through them restricted by the operation of the valves 270 a, 270B, and third and fourth coil paths 180C, 180D pass refrigerant regardless of the configuration of the valves 270. Thus, the valves 270 can restrict one or two of the coil paths 180 from receiving refrigerant. If the coil paths 180 are all the same size, that means that two reduced capacity operations are possible: one at 50% of the maximum capacity and one at 75% of the maximum capacity. If the coil paths 180 are different sizes, the reduced capacities of these modes will depend upon the percentage of total refrigerant flow that can be restricted by the valves 270.

Alternate embodiments can alter the number of coil paths 180, the sizes of the various coil paths 180, and the number of valves 270 to provide desired reduced capacity percentages.

Third Disclosed Embodiment

FIG. 3 is a diagram of an air-conditioning unit 300 having an air-conditioning coil 105 whose capacity can be controlled according to third disclosed embodiments.

As shown in FIG. 3, the air-conditioning unit 300 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a refrigerant distributor 120, an expansion valve 125, a refrigerant flow pipe 130, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, a plurality of nodes 160A-160D, and a plurality of valves 375A, 375B. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105.

The air-conditioning coil 105, the input vent 110, the output vent 115, the refrigerant distributor 120, the expansion valve 125, the refrigerant flow pipe 130, the plurality of first refrigerant lines 140A-140D, the plurality of second refrigerant lines 150A-150D, the third refrigerant line 155, the plurality of nodes 160A-160D, and the plurality of coil paths 180A-180D operate essentially as described above with respect to the embodiment of FIG. 1. As a result, a description of these elements with similar reference numbers will not be repeated. Unlike the embodiment of FIG. 1, no valve 170 is provided on the third refrigerant line 155.

The plurality of valves 375A and 375B are provided on the first refrigerant lines 140A and 140B, respectively. The valves 375 are each designed such that they always pass refrigerant in a direction that the refrigerant flows during a heating mode and may selectively stop the flow of refrigerant in the direction the refrigerant flows during a cooling mode. The valves 375 can be bi-flow directional solenoid valves, a combined solenoid valve and check valve, a linear expansion valve, a direct-acting solenoid valve, a different kind of suitable valve, or a combination of these types of valves. The valves 375 are controllable by control signals received from an air-conditioner controller (not shown).

The valves 375 each have at least two settings. A first setting allows refrigerant to flow freely through the valve 375 in both directions. This corresponds to the air-conditioning coil 105 operating at full capacity. A second setting allows refrigerant to freely flow through the valve 375 in a direction that refrigerant flows during a heating mode but stops the flow of refrigerant in the direction that the refrigerant flows during a cooling mode. This corresponds to the air-conditioning coil 105 operating at reduced capacity.

Each valve 375 can therefore selectively block the flow of cooled refrigerant through the first refrigerant line 140 it is located on and therefore through the corresponding coil path 180 connected to that first refrigerant line 140 during a cooling mode. In doing so, the valve 375 can selectively turn on and off the coil paths 180 connected to the first refrigerant line 140 the valve 375 is located on during a cooling mode, thus selecting between a cooling mode at full capacity and one or more cooling modes at reduced capacity.

In the embodiment of FIG. 3, the valves 375 are located on the first refrigerant lines 140A and 140B and so can selectively stop the flow of cooled refrigerant into first and second coil paths 180A and 180B selected from four total coil paths 180A-180D. However, this is by way of example only. Alternate embodiments can employ more or fewer coil paths 180. Furthermore, valves 375 may be placed at more or fewer first refrigerant lines 140, allowing them to control the flow of cooled refrigerant into a different subset of the coil paths 180.

In operation, the air-conditioning unit 300 can operate in at least three different modes: a heating mode, a cooling mode at full capacity, and at least one cooling mode at reduced capacity. The air-conditioning unit 300 will choose between a heating mode and a cooling mode using conventional air-conditioner elements not shown in FIG. 3. When in a cooling mode, the air-conditioning unit 300 will determine whether it operates at full capacity or reduced capacity based on the configuration of the valves 375. When all the valves 375 allow refrigerant to pass through them in a cooling mode, the air-conditioning unit 300 will operate at full capacity; and when at least one valve 375 restricts refrigerant flow through it in a cooling mode, the air-conditioning unit 300 will operate at reduced capacity.

Furthermore, if each valve 375 is operable independent of the other valves 375, multiple reduced-capacity cooling modes can be provided by varying which valves 375 allow refrigerant to pass through them during a cooling mode and which valves 375 stop refrigerant passing through them during a cooling mode. For example, in the embodiment of FIG. 3, a first reduced-capacity cooling mode can correspond to both valves 375 stopping refrigerant passing through them during a cooling mode, and a second reduced-capacity cooling mode can correspond to one valve 375 allowing refrigerant to pass through it and one valve 375 stopping refrigerant from passing through it during a cooling mode.

Furthermore, if the coil paths 180 corresponding to the valves 375 are of different sizes, the air-conditioning unit 300 can have three reduced-capacity cooling modes. A first reduced-capacity cooling mode can correspond to both valves 375A, 375B restricting refrigerant passing through them, a second reduced-capacity cooling mode can correspond to valve 375A allowing refrigerant to pass through it and valve 375B restricting refrigerant from passing through it, and a third reduced-capacity cooling mode can correspond to valve 375B allowing refrigerant to pass through it and valve 375A restricting refrigerant from passing through it.

In all these possible modes, refrigerant flows through one or more of the coil paths 180 to or from the first, second, and third refrigerant lines 140, 150, 155. This refrigerant will be heated above the ambient temperature in the zone to be heated during a heating mode and will be cooled below the ambient temperature in the zone to be cooled during a cooling mode. Return air will be drawn into the input vent 110 and will be passed through the air-conditioning coil 105 where it will exchange heat with the refrigerant passing through the air-conditioning coil 105, heating or cooling the return air as appropriate. The heated or cooled return air will then exit the air-conditioning coil 105 into the output vent 115 as supply air. The supply air will then be provided to the zone that the air-conditioning unit 300 services.

During a heating mode, heated refrigerant will be provided to the third refrigerant line 155, which will distribute the heated refrigerant to the second refrigerant lines 150, respectively. The refrigerant will therefore pass from the third refrigerant line 155 through each of the second refrigerant lines 150 into respective coil paths 180 where it will exchange heat with the return air passing through the air-conditioning coil 105. This heat exchange operation will heat the return air and cool the refrigerant. The heated return air will pass to the output vent 115 as heated supply air, while the cooled refrigerant will pass from the respective coil paths 180 to respective first refrigerant lines 140, and that there through the refrigerant distributor 120, the expansion valve 125, and the refrigerant flow pipe 130. The valves 375 are each configured to allow the heated refrigerant to continually flow through them when it is flowing in a heating mode. From the refrigerant flow pipe 130 the cooled refrigerant will pass through the remainder of the air-conditioning unit 300, where it will be reheated and provided again to the third refrigerant line 155 as heated refrigerant.

During a full-capacity cooling mode, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, which will control the amount of refrigerant it passes, as appropriate. Cooled refrigerant will then be passed from the expansion valve 125 to the single opening on the first side of the refrigerant distributor 120. The refrigerant distributor 120 will then distribute the cooled refrigerant to each of the plurality of first refrigerant lines 140 at the corresponding plurality of openings on the second side of the refrigerant distributor 120.

The cooled refrigerant will pass through each of the first refrigerant lines 140 into openings at first ends of each of the corresponding coil paths 180 and will fill the corresponding coil paths 180 with cooled refrigerant. The cooled refrigerant will then pass through the coil paths 180 and will fill corresponding second refrigerant lines 150.

In the full-capacity cooling mode, the valves 375 will all be set such that the cooled refrigerant can freely flow through them during a cooling mode. As a result, cooled refrigerant will pass from the refrigerant distributor 120 through all the first refrigerant lines 140 to the corresponding coil paths 180. In this way, all the coil paths 180 will have cooled refrigerant circulating through them during the cooling mode. As a result, air passing over all the coil paths 180 will exchange heat with the refrigerant flowing through the coil paths 180, thus cooling the air.

This heat exchange operation will cool the return air and heat the refrigerant. The cooled return air will pass to the output vent 115 as cooled supply air, while the heated refrigerant from all the coil paths 180 will pass from the coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 300, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

The cooled refrigerant will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through a coil path 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each of the coil paths 180 will be both cooled and dehumidified.

In the one or more reduced-capacity cooling modes, cooled refrigerant will be provided to the refrigerant flow pipe 130 and from there to the expansion valve 125, the refrigerant distributor 120, and the plurality of first refrigerant lines 140. However, during the reduced-capacity cooling mode, at least one valve 375 will be configured such that the cooled refrigerant cannot flow through it during a cooling mode.

For coil paths 180C, 180D whose associated first refrigerant line 140C, 140D does not have a valve 375, cooled refrigerant will pass from the refrigerant distributor 120, through the first refrigerant lines 140C, 140D to the corresponding coil path 180, through the corresponding second refrigerant line 150, through the third refrigerant line 155, and on to the remainder of the air-conditioning unit 300 without interference. For coil paths 180 whose associated first refrigerant line 140 have a valve 375, but whose valve 375 is set to permit the flow of cooled refrigerant, the cooled refrigerant will pass from the refrigerant distributor 120, through the corresponding first refrigerant line 140 to the corresponding coil path 180, through the corresponding second refrigerant line 150, through the third refrigerant line 155, and on to the remainder of the air-conditioning unit 300 without interference. However, for coil paths 180 whose associated first refrigerant line 140 has a valve 375, but whose valve 375 is set to stop the flow of cooled refrigerant, the cooled refrigerant will pass from the refrigerant distributor 120, and will fill up a portion of the corresponding first refrigerant lines 140 upstream of the valve 375 but will not pass through the portion of the first refrigerant line 140 downstream of the valve 375 and on to the corresponding coil path 180, through the corresponding second refrigerant line 150, through the third refrigerant line 155, and on to the remainder of the air-conditioning unit 200 without interference.

Since no cooled refrigerant will reach coil paths 180 that correspond to closed valves 375, these corresponding coil paths 180 will never fill with cooled refrigerant and will never have cooled refrigerant circulate through them. During a reduced-capacity cooling operation, only air passing over coil paths 180 that have refrigerant flowing through them will be cooled and dehumidified. Air passing over coil path 180 that do not have refrigerant flowing through it will be neither cooled nor dehumidified.

However, while one or more coil paths 180 will pass unconditioned return air that is neither cooled nor dehumidified, one or more coil paths 180 will pass conditioned return air that has been both cooled and dehumidified. Since the return air from all the coil paths 180 is combined to form the supply air, the resulting supply air will still be both cooler and less humid than the return air provided to the plurality of coil paths 180. Thus, despite performing its cooling at a lower capacity in fewer than all the coil paths 180, the air-conditioning unit 300 will still act to both cool the return air that passes through it and remove moisture from the return air it cools.

The heat exchange operation performed during a reduced-capacity cooling mode will cool a portion of the return air and heat the refrigerant. The cooled return air will pass to the output vent 115, combined with uncooled return air to form cooled supply air, while the heated refrigerant from all coil paths 180 it circulates through will pass from coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 300, where it will be recooled and provided again to the refrigerant flow pipe 130 as cooled refrigerant.

Again, the cooled refrigerant will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through one or more coil paths 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each coil path 180 that has refrigerant flowing through it will be both cooled and dehumidified.

The full-capacity cooling mode is referred to as being at “full capacity” since all the coil paths 180 operate to cool and dehumidify the return air. The reduced-capacity cooling mode is referred to as being at “reduced capacity” because fewer than all the coil paths 180 operate to cool and dehumidify the return air.

The air-conditioning coil 105 will therefore remove moisture from the return air in both the full-capacity cooling mode and any reduced-capacity cooling mode because the refrigerant supplied to the air-conditioning coil 105 will be at a temperature in both cooling modes that is low enough to condense moisture from air passing over coil paths 180 containing the cooled refrigerant. In other words, the air-conditioning unit 300 will provide enough cooling to the refrigerant for dehumidification whether the air-conditioning unit 300 is operating at full capacity or reduced capacity. Because the cooled refrigerant will be at a sufficiently low temperature for dehumidification, it will be cold enough to cause moisture to condense from the return air as the return air passes over any of the coil paths 180 in which cooled refrigerant is circulating, whether it is all the coil paths 180 in full capacity operation or only some of the coil paths 180 in reduced capacity operation.

The reduced capacity of the air-conditioning coil is set based on which coil paths 180 are be restricted by the operation of the valves 375. For example, in the exemplary embodiment shown by FIG. 3, the first and second coil paths 180A, 180B can have flow of refrigerant through them restricted by the operation of the valves 375A, 375B, and third and fourth coil paths 180C, 180D pass refrigerant regardless of the configuration of the valves 375. Thus, the valves 375 can restrict one or two of the coil paths 180 from receiving refrigerant. If the coil paths 180 are all the same size, that means that two reduced capacity operations are possible: one at 50% of the maximum capacity and one at 75% of the maximum capacity. If the coil paths 180 are different sizes, the reduced capacities of these modes will depend upon the percentage of total refrigerant flow that can be restricted by the valves 375.

Alternate embodiments can alter the number of coil paths 180, the sizes of the various coil paths 180, and the number of valves 375 to provide desired reduced capacity percentages.

Fourth Disclosed Embodiment

FIG. 4 is a diagram of an air-conditioning unit 400 having an air-conditioning coil 105 whose capacity can be controlled according to fourth disclosed embodiments.

As shown in FIG. 4, the air-conditioning unit 400 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a refrigerant distributor 120, an expansion valve 125, a refrigerant flow pipe 130, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, a plurality of nodes 160A-160D, and a valves 475. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105.

The air-conditioning coil 105, the input vent 110, the output vent 115, the refrigerant distributor 120, the expansion valve 125, the refrigerant flow pipe 130, the plurality of first refrigerant lines 140A-140D, the plurality of second refrigerant lines 150A-150D, the third refrigerant line 155, the plurality of nodes 160A-160D, the plurality of coil paths 180A-180D operate essentially as described above with respect to the embodiment of FIG. 1. As a result, a description of these elements will not be repeated. Unlike the embodiment of FIG. 3, only one valve 475 is provided on a single first refrigerant line 140.

The valve 475 operates essentially the same as the valve 375A in FIG. 3. As such, the description of the valve 375A in specific and the valves 375 in general applies to valve 475.

The embodiment of FIG. 4 differs from the embodiment of FIG. 3 in that the air-conditioning unit 400 only has a single valve 475 on a single first refrigerant line 140. As a result, the air-conditioning unit 400 can only have a single reduced-capacity cooling mode. In other words, a full-capacity cooling mode corresponds to a situation in which the valve 475 is set to allow cooled refrigerant to flow in a direction used during a cooling mode and a reduced capacity cooling mode corresponds to a situation in which the valve 475 is set to restrict cooled refrigerant from flowing in a direction used during a cooling mode. Otherwise, the embodiment of FIG. 4 operates essentially as described below with respect to the embodiment of FIG. 3. The description of the embodiment of FIG. 3 therefore applies to the embodiment of FIG. 4, except where the embodiment of FIG. 3 requires two or more valves 375.

Fifth Disclosed Embodiment

FIG. 5 is a diagram of an air-conditioning unit 500 having an air-conditioning coil 105 whose capacity can be controlled according to fifth disclosed embodiments.

As shown in FIG. 5, the indoor air-conditioning unit 500 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a first refrigerant distributor 520A, a second refrigerant distributor 520B, a first expansion valve 525A, a second expansion valve 525B, a refrigerant flow pipe 530, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, and a plurality of nodes 160A-160D. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105.

The air-conditioning coil 105, the input vent 110, the output vent 115, the plurality of first refrigerant lines 140A-140D, the plurality of second refrigerant lines 150A-150D, the third refrigerant line 155, the plurality of nodes 160A-160D, and the plurality of coil paths 180A-180D operate essentially as described above with respect to the embodiment of FIG. 1. As a result, a description of these elements will not be repeated. Unlike the embodiment of FIG. 1, no valve 170 is provided on the third refrigerant line 155.

The first refrigerant distributor 520A operates essentially as does the refrigerant distributor 120 of FIG. 1 save that it is connected at a first side to the first expansion valve 525A and at a second side to a first plurality of first refrigerant lines 140 that includes fewer than all of the first refrigerant lines 140. Therefore, the description of the refrigerant distributor 120 of FIG. 1 applies to the first refrigerant distributor 520A, save that the number of openings on the second side are different and they are connected to fewer than all the first refrigerant lines 140.

Similarly, The second refrigerant distributor 520B operates essentially as does the refrigerant distributor 120 of FIG. 1 save that it is connected at a first side to the second expansion valve 525B and at a second side to a second plurality of first refrigerant lines 140 that includes fewer than all of the first refrigerant lines 140. Therefore, the description of the refrigerant distributor 120 of FIG. 1 applies to the second refrigerant distributor 520B, save that the number of openings on the second side are different and they are connected to fewer than all the first refrigerant lines 140.

Furthermore, the first and second refrigerant distributors 520A, 520B are arranged such that together they connect to all the first refrigerant lines 140, but that each first refrigerant line 140 is only connected to one of the first and second refrigerant distributors 520A, 520B.

For ease of disclosure, the first and second refrigerant distributors 520A, 520B may be referred to, individually or collectively, as refrigerant distributors 520.

The first expansion valve 525A operates essentially as does the expansion valve 125 of FIG. 1 save that it is connected between the first refrigerant distributor 520A and the refrigerant flow pipe 530. Therefore, the description of the expansion valve 125 of FIG. 1 applies to the first expansion valve 525A, save that the first expansion valve 525A only controls the amount of refrigerant provided to the coil paths 180 in the air-conditioning coil 105 that are connected to the first plurality of first refrigerant lines 140 connected to the first refrigerant distributor 520A.

Similarly, the second expansion valve 525B operates essentially as does the expansion valve 125 of FIG. 1 save that it is connected between the second refrigerant distributor 520B and the refrigerant flow pipe 530. Therefore, the description of the expansion valve 125 of FIG. 1 applies to the second expansion valve 525B, save that the second expansion valve 525B only controls the amount of refrigerant provided to the coil paths 180 in the air-conditioning coil 105 that are connected to the second plurality of first refrigerant lines 140 connected to the second refrigerant distributor 520B.

For ease of disclosure, the first and second expansion valves 525A, 525B may be referred to, individually or collectively, as expansion valves 525.

The refrigerant flow pipe 530 operates essentially as does the refrigerant flow pipe 130 of FIG. 1 save that it allows refrigerant to flow to and from both the first and second expansion valves 525A, 525B with respect to the remainder of the air-conditioning system 500 not shown in FIG. 1. The refrigerant flow pipe 530 is connected between both the first and second expansion valves 525A, 525B and the remainder of the air-conditioning system 500 that is not shown in FIG. 5.

The first expansion valve 525A controls the amount of refrigerant that passes from the refrigerant flow pipe 530 into the first refrigerant distributor 520A and therefore into the first plurality of first refrigerant lines 140. In addition to limiting the amount of refrigerant that passes from the refrigerant flow pipe 530 into the first refrigerant distributor 520A, the first expansion valve 525A can be set to completely cut off the flow of refrigerant from the refrigerant flow pipe 530 into the first refrigerant distributor 520A and into the first plurality of first refrigerant lines 140. The first expansion valve 525A is controllable by control signals received from an air-conditioner controller (not shown).

The second expansion valve 525B controls the amount of refrigerant that passes from the refrigerant flow pipe 530 into the second refrigerant distributor 520B and therefore into the second plurality of first refrigerant lines 140. In addition to limiting the amount of refrigerant that passes from the refrigerant flow pipe 530 into the second refrigerant distributor 520B, the second expansion valve 525B can be set to completely cut off the flow of refrigerant from the refrigerant flow pipe 530 into the second refrigerant distributor 520B and into the second plurality of first refrigerant lines 140. The second expansion valve 525B is controllable by control signals received from an air-conditioner controller (not shown).

Each expansion valve 525A, 525B can therefore selectively block the flow of cooled refrigerant during a cooling mode through the group of first refrigerant lines 140 it is associated with and therefore through the corresponding coil paths 180 connected to those first refrigerant lines 140. In doing so, the expansion valves 525A, 525B can selectively turn on and off the coil paths 180 during a cooling mode that are connected to the first refrigerant lines 140 the expansion valves 525A, 525B are associated with, thus selecting between a cooling mode at full capacity and a cooling mode at reduced capacity.

In the embodiment of FIG. 5, the first expansion valve 525A is associated with the first refrigerant lines 140A and 140B and so can selectively stop the flow of cooled refrigerant into two coil paths 180A and 180B selected from four total coil paths 180A-180D. Likewise, the second expansion valve 525B is associated with the first refrigerant lines 140C and 140D and so can selectively stop the flow of cooled refrigerant into two coil paths 180C and 180D selected from four total coil paths 180A-180D. However, this is by way of example only. Alternate embodiments can employ more or fewer coil paths 180, or more sets of refrigerant distributors 520 and expansion valves 525. Furthermore, the expansion valves 525A, 525B may be associated with different first and second pluralities of placed at more or fewer first refrigerant lines 140, allowing them to control the flow of cooled refrigerant into a different subset of the coil paths 180.

In operation, the air-conditioning unit 500 can operate in at least three different modes: a heating mode, a cooling mode at full capacity, and at least one cooling mode at reduced capacity. The air-conditioning unit 500 will choose between a heating mode and a cooling mode using conventional air-conditioner elements not shown in FIG. 5. When in a cooling mode, the air-conditioning unit 500 will determine whether it operates at full capacity or reduced capacity based on the configuration of the expansion valves 525A, 525B. When all the expansion valves 525A, 525B allow refrigerant to pass through them in a cooling mode, the air-conditioning unit 500 will operate at full capacity; and when at least one expansion valve 525A, 525B cuts off refrigerant flow through it in a cooling mode, the air-conditioning unit 500 will operate at reduced capacity.

Furthermore, if the total percentage of the size of the air-conditioning coil 105 that is connected to each expansion valve 525A, 525B is not the same, multiple reduced-capacity cooling modes can be provided by varying which expansion valve 525A, 525B allows refrigerant to pass through it and which expansion valve 525A, 525B cuts off refrigerant passing through it. For example, in the embodiment of FIG. 5, a first reduced-capacity cooling mode can correspond to the first expansion valves 525A passing refrigerant and the second expansion valve 525B cutting off the flow of cooled refrigerant, and a second reduced-capacity cooling mode can correspond to the second expansion valves 525B passing refrigerant and the first expansion valve 525A cutting off the flow of cooled refrigerant.

In all these possible modes, refrigerant flows through one or more of the coil paths 180 to or from the first, second, and third refrigerant lines 140, 150, 155. This refrigerant will be heated above the ambient temperature in the zone to be heated during a heating mode and will be cooled below the ambient temperature in the zone to be cooled during a cooling mode. Return air will be drawn into the input vent 110 and will be passed through the air-conditioning coil 105 where it will exchange heat with the refrigerant passing through the air-conditioning coil 105, heating or cooling the return air as appropriate. The heated or cooled return air will then exit the air-conditioning coil 105 into the output vent 115 as supply air. The supply air will then be provided to the zone that the air-conditioning unit 500 services.

During a heating mode, heated refrigerant will be provided to the third refrigerant line 155, which will distribute the heated refrigerant to the second refrigerant lines 150, respectively. The refrigerant will therefore pass from the third refrigerant line 155 through each of the second refrigerant lines 150 into respective coil paths 180 where it will exchange heat with the return air passing through the air-conditioning coil 105. This heat exchange operation will heat the return air and cool the refrigerant. The heated return air will pass to the output vent 115 as heated supply air, while the cooled refrigerant will pass from the respective coil paths 180 to respective first refrigerant lines 140, and that there through the first and second refrigerant distributors 520A, 520B, the first and second expansion valves 525A, 525B, and the refrigerant flow pipe 530. The expansion valves 525 are each set to allow cooled refrigerant to continually flow through them when it is flowing in a heating mode. From the refrigerant flow pipe 530 the cooled refrigerant will pass through the remainder of the air-conditioning unit 500, where it will be reheated and provided again to the third refrigerant line 155 as heated refrigerant.

During a full-capacity cooling mode, cooled refrigerant will be provided to the refrigerant flow pipe 530 and from there to the first and second expansion valves 525A, 525B, which will control the amount of refrigerant they pass, as appropriate. The first and second expansion valves 525A, 525B will be configured to allow at least some cooled refrigerant to pass through them.

Cooled refrigerant will then be passed from the first and second expansion valves 525A, 525B to the first and refrigerant distributors 520A, 520B, respectively. The refrigerant distributors 520 will then distribute the cooled refrigerant to the first and second plurality of first refrigerant lines 140 at the corresponding plurality of openings on the second sides of the refrigerant distributors 520.

The cooled refrigerant will pass through each of the first refrigerant lines 140 into openings at first ends of each of the corresponding coil paths 180 and will fill the corresponding coil paths 180 with cooled refrigerant. The cooled refrigerant will then pass through the coil paths 180 and will fill corresponding second refrigerant lines 150.

Since the first and second expansion valves 525A, 525B are both set such that the cooled refrigerant can freely flow through them, cooled refrigerant will pass from the refrigerant distributor 120 through all the first refrigerant lines 140 to the corresponding coil paths 180. In this way, all the coil paths 180 will have cooled refrigerant circulating through them. As a result, air passing over all the coil paths 180 will exchange heat with the refrigerant flowing through the coil paths 180, thus cooling the air.

This heat exchange operation will cool the return air and heat the refrigerant. The cooled return air will pass to the output vent 115 as cooled supply air, while the heated refrigerant from all the coil paths 180 will pass from the coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 500, where it will be recooled and provided again to the refrigerant flow pipe 530 as cooled refrigerant.

The cooled refrigerant will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through a coil path 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each of the coil paths 180 will be both cooled and dehumidified.

In the one or more reduced-capacity cooling modes, cooled refrigerant will be provided to the refrigerant flow pipe 530 and from there to the first and second expansion valves 525A, 525B. One of the first and second expansion valves 525A, 525B will be configured to allow at least some cooled refrigerant to pass through it during a cooling mode, while the other of the first and second expansion valves 525A, 525B will be configured to cut off the flow of cooled refrigerant through it during a cooling mode.

The refrigerant distributor 520 associated with the expansion valve 525 that passes cooled refrigerant will receive the cooled refrigerant and pass it on to the portion of the plurality of first refrigerant lines 140 associated with the expansion valve 525 that passes cooled refrigerant. The refrigerant distributor 520 associated with the expansion valve 525 that cuts off the passage of cooled refrigerant will receive no cooled refrigerant. Thus, the portion of the plurality of first refrigerant lines 140 associated with the expansion valve 525 that cuts off the passage of cooled refrigerant during a cooling mode will likewise receive no cooled refrigerant.

For coil paths 180 whose corresponding first refrigerant line 140 is associated with the expansion valve 525 that passes cooled refrigerant during a cooling mode, the cooled refrigerant will pass from the refrigerant distributor 520, through the corresponding first refrigerant line 140 to the corresponding coil path 180, through the corresponding second refrigerant line 150, through the third refrigerant line 155, and on to the remainder of the air-conditioning unit 500 without interference. For coil paths 180 whose corresponding first refrigerant line 140 is associated with the expansion valve 525 that cuts off the passage of cooled refrigerant during a cooling mode, the cooled refrigerant will pass from the refrigerant distributor 530 to the expansion valve 525 but will not pass to the corresponding refrigerant distributor 520 or through the corresponding first refrigerant lines 140 to the corresponding coil path 180.

Since no cooled refrigerant will reach coil paths 180 that correspond to the closed expansion valve 525, these corresponding coil paths 180 will never fill with cooled refrigerant and will never have cooled refrigerant circulate through them. During a reduced-capacity cooling operation, only air passing over coil paths 180 that have refrigerant flowing through them will be cooled and dehumidified. Air passing over coil path 180 that do not have refrigerant flowing through it will be neither cooled nor dehumidified.

However, while one or more coil paths 180 will pass unconditioned return air that is neither cooled nor dehumidified, one or more coil paths 180 will pass conditioned return air that has been both cooled and dehumidified. Since the return air from all the coil paths 180 is combined to form the supply air, the resulting supply air will still be both cooler and less humid than the return air provided to the plurality of coil paths 180. Thus, despite performing its cooling at a lower capacity in fewer than all the coil paths 180, the air-conditioning unit 500 will still act to both cool the return air that passes through it and remove moisture from the return air it cools.

The heat exchange operation performed during a reduced-capacity cooling mode will cool a portion of the return air and heat the refrigerant. The cooled return air will pass to the output vent 115, combined with uncooled return air to form cooled supply air, while the heated refrigerant from all coil paths 180 it circulates through will pass from coil paths 180 to respective second refrigerant lines 150, and there to the third refrigerant line 155. From the third refrigerant line 155 the heated refrigerant will pass through the remainder of the air-conditioning unit 500, where it will be recooled and provided again to the refrigerant flow pipe 530 as cooled refrigerant.

As in the full-capacity cooling mode, the cooled refrigerant in the reduced capacity cooling mode will be cooled to a temperature low enough that when return air exchanges heat with the cooled refrigerant passing through one or more coil paths 180, moisture will condense from the passing return air onto the coil path 180. As a result, air passing over each coil path 180 that has refrigerant flowing through it will be both cooled and dehumidified.

The full-capacity cooling mode is referred to as being at “full capacity” since all the coil paths 180 operate to cool and dehumidify the return air. The reduced-capacity cooling mode is referred to as being at “reduced capacity” because fewer than all the coil paths 180 operate to cool and dehumidify the return air.

The air-conditioning coil 105 will therefore remove moisture from the return air in both the full-capacity cooling mode and any reduced-capacity cooling mode because the refrigerant supplied to the air-conditioning coil 105 will be at a temperature in both cooling modes that is low enough to condense moisture from air passing over coil paths 180 containing the cooled refrigerant. In other words, the air-conditioning unit 500 will provide enough cooling to the refrigerant for dehumidification whether the air-conditioning unit 500 is operating at full capacity or reduced capacity. Because the cooled refrigerant will be at a sufficiently low temperature for dehumidification, it will be cold enough to cause moisture to condense from the return air as the return air passes over any of the coil paths 180 in which cooled refrigerant is circulating, whether it is all the coil paths 180 in full capacity operation or only some of the coil paths 180 in reduced capacity operation.

The reduced capacity of the air-conditioning coil is set based on which coil paths 180 are be restricted by the operation of the expansion valves 525. For example, in the exemplary embodiment shown by FIG. 5, the first and second coil paths 180A, 180B can have flow of refrigerant through them restricted by the operation of the first expansion valve 525A and the third and fourth coil paths 180C, 180D can have flow of refrigerant through them restricted by the operation of the second expansion valve 525B. If the coil paths 180 are all the same size, that means that one reduced capacity operations is possible, i.e., at 50% of the maximum capacity. If the coil paths 180 are different sizes, the reduced capacities of these modes will depend upon the percentage of total refrigerant flow that can be restricted by the expansion valves 525.

Alternate embodiments can alter the number of coil paths 180, the sizes of the various coil paths 180, the number of expansion valves 525, and the connections of the first refrigerant lines 140 to the refrigerant distributors 520 to provide desired reduced capacity percentages.

Sixth Disclosed Embodiment

FIG. 6 is a diagram of an indoor air-conditioning unit 600 having an air-conditioning coil 105 whose capacity can be controlled according to sixth disclosed embodiments.

As shown in FIG. 6, the indoor air-conditioning unit 600 includes an air-conditioning coil 105, an input vent 110, an output vent 115, a refrigerant distributor 120, an expansion valve 125, a refrigerant flow pipe 130, a plurality of first refrigerant lines 140A-140D, a plurality of second refrigerant lines 150A-150D, a third refrigerant line 155, a plurality of nodes 160A-160D, a first valve 270, and a second valve 475. The air-conditioning coil 105 is divided into a plurality of coil paths 180A-180D that are arranged in parallel with respect to the flow of air through the air-conditioning coil 105.

The air-conditioning coil 105, the input vent 110, the output vent 115, the refrigerant distributor 120, the expansion valve 125, the refrigerant flow pipe 130, the plurality of first refrigerant lines 140A-140D, the plurality of second refrigerant lines 150A-150D, the third refrigerant line 155, the plurality of nodes 160A-160D, the plurality of coil paths 180A-180D, the first valves 270, and the second valve 475 operate essentially as described above for similarly numbered items in the embodiments of FIGS. 1, 2, and 4. As a result, a description of these elements will not be repeated.

The embodiment of FIG. 6 differs from the embodiments of FIGS. 1-4 in that the flow of cooled refrigerant through the coil paths 180 during a cooling mode is controlled by a combination of valves 270 and 475. In other words, the flow of cooled refrigerant through the coil paths 180 can be controlled from either side of the air-conditioning coil 105 and using any of the elements described above in the embodiments of FIGS. 1-5.

Furthermore, although not specifically shown in FIG. 6, alternate embodiments could combine any of valves 170, 270, 375, 475 or expansion valves 525 in various configurations to control the flow of cooled refrigerant through the coil paths 180.

ALTERNATE EMBODIMENTS

Although the embodiments of FIGS. 1-3, 5, and 6 show configurations in which two out of four of the coil paths 180 can be blocked using the various valves 170, 270A, 270B, 375A, 375B, 475 and expansion valves 525A, 525B, and FIG. 4 shows a configuration in which one out of four of the coil paths 180 can be blocked using the valve 475, this is by way of example only. Alternate embodiments can use different combinations of valves 170, 270, 375, 475, 525 to control the passage of refrigerant through any combination of coil paths 180.

Also, while the disclosed embodiments each show that the air-conditioning coil 105 is divided into four coil paths 180 of equal size, this is by way of example only. Alternate embodiments can divide the air-conditioning coil 105 into any number of coil paths 180 and the coil paths need not be of the same size. The exact combination of coil path 180 numbers and sizes as well as the number and placement of valves 170, 270, 375, 475, 525 will determine the possible coil capacities that can be selected.

Valve Configuration

FIGS. 7A-7C are diagrams of a valve 170, 270 used in the embodiments of FIGS. 1, 2, and 6 according to disclosed embodiments. FIG. 7A is a diagram showing the operation of the valves 170, 270 during a heating mode; FIG. 7B is a diagram showing the operation of the valves 170, 270 during a cooling mode at full capacity; and FIG. 7C is a diagram showing the operation of the valves 170, 270 during a cooling mode at reduced capacity.

As shown in FIGS. 7A-7C, the valve 170, 270 includes a main refrigerant path 710, a bypass refrigerant path 720, a first valve structure 730 and a second valve structure 740. The first valve structure is located on the main refrigerant path 710 between a first path connection 750 and a second path connection 760. The bypass refrigerant path 720 is connected to the main refrigerant path 710 on a first end at the first path connection 750 and on a second end at the second path connection 760. The second valve structure 740 is located on the bypass refrigerant path 720 between the first path connection 750 and the second path connection 760.

The main refrigerant path 710 and the bypass refrigerant path 720 are both tubes or pipes that are designed to carry refrigerant.

The first valve structure 730 is a valve that always prohibits refrigerant flow in a first direction and selectively prohibits refrigerant flow in a second direction. The first valve structure 730 is arranged such that it will always prohibit the flow of refrigerant in the direction that the refrigerant flows during a heating mode and will selectively prohibit the flow of refrigerant in the direction that refrigerant flows during a cooling mode. The first valve structure 730 may be controlled by a control signal received from a controller (not shown). The first valve structure 730 may be a controllable solenoid valve that prohibits the passage of refrigerant in a first direction and selectively allows or prohibits the flow of refrigerant in a second direction.

The second valve structure 740 is a valve that always prohibits refrigerant flow in a first direction and always allows refrigerant flow in a second direction. The second valve structure 740 is arranged such that it will always prohibit the flow of refrigerant in the direction that the refrigerant flows during a cooling mode and will always allow the flow of refrigerant in the direction that refrigerant flows during a heating mode. The second valve structure may be a one-way check valve.

As shown in FIG. 7A, during a heating mode the first valve structure 730 will always prohibit the flow of refrigerant while the second valve structure 740 will always allow the flow of refrigerant. This is true regardless of how the first valve structure 730 is set. Since the second valve structure 740 will always allow the flow of refrigerant in the direction it passes during a heating mode, the valve 170, 270 will always pass refrigerant from a first side to a second side without restriction during a heating mode.

As shown in FIG. 7B, during a cooling mode at full capacity the second valve structure 740 will always prohibit the flow of refrigerant in the direction it flows during the cooling mode while the first valve structure 730 will be set to allow the flow of refrigerant in the direction it flows during the cooling mode. During the cooling mode at full capacity the valve 170, 270 will allow the flow of refrigerant in the direction it passes during the cooling mode.

As shown in FIG. 7C, during a cooling mode at reduced capacity the second valve structure 740 will always prohibit the flow of refrigerant in the direction it flows during the cooling mode while the first valve structure 730 will be set to prohibit the flow of refrigerant in the direction it flows during the cooling mode. During the cooling mode at reduced capacity the valve 170, 270 will prohibit the flow of refrigerant in the direction it passes during the cooling mode.

Therefore, as shown in FIGS. 7B and 7C, the first valve structure 730 can be selectively controlled to either pass refrigerant in the direction it flows during a cooling mode or to prohibit the passage of refrigerant in the direction it flows during a cooling mode. In this way the entire valve 170, 270 can be controlled to either pass refrigerant or prohibit the passage of refrigerant in the direction it flows during a cooling mode.

Typically, the valve structure of FIGS. 7A-7C is only used on the side of the air-conditioning coil 105 that is downstream with respect to the flow of refrigerant during a cooling mode and upstream of the flow of refrigerant during a heating mode. This is because the valve designs generally used for the first and second valve structures 730, 740 are of a size that functions well with refrigerant in a gaseous state as it would be downstream of the air-conditioning coil 105 during a cooling mode and upstream of the air-conditioning coil 105 during a heating mode and not refrigerant in a liquid state as it would be upstream of the air-conditioning coil 105 during a cooling mode and downstream of the air-conditioning coil 105 during a heating mode. As a result, the valve structure of FIGS. 7A-7C will generally be used for the valves 170 and 270, but not the valves 375 and 475.

FIGS. 8A-8C are diagrams of a valve 170, 270, 375, 475 used in the embodiments of FIGS. 1-4 and 6 according to alternate disclosed embodiments. FIG. 8A is a diagram showing the operation of the valves 170, 270, 375, 475 during a heating mode; FIG. 8B is a diagram showing the operation of the valves 170, 270, 375, 475 during a cooling mode at full capacity; and FIG. 8C is a diagram showing the operation of the valves 170, 270, 375, 475 during a cooling mode at reduced capacity.

As shown in FIGS. 8A-8C, the valve 170, 270, 375, 475 includes a main refrigerant path 810 and a valve structure 830. The valve structure 830 is located on the main refrigerant path 810

The main refrigerant path 810 is a tube or pipe that is designed to carry refrigerant.

The valve structure 830 is a valve that always allows refrigerant flow in a first direction and selectively prohibits refrigerant flow in a second direction. The valve structure 830 is arranged such that it will always allow the flow of refrigerant in the direction that the refrigerant flows during a heating mode and will selectively prohibit the flow of refrigerant in the direction that refrigerant flows during a cooling mode. The valve structure 830 may be controlled by a control signal received from a controller (not shown). In some embodiments the valve structure may be a bidirectional solenoid valve for the valves 170, 270 and may be a direct-action solenoid for valves 375, 475.

As shown in FIG. 8A, during a heating mode the first valve structure 830 will always allow the flow of refrigerant. This is true regardless of how the valve structure 830 is set. Thus, the valve 170, 270, 375, 475 will always pass refrigerant from a first side to a second side without restriction during a heating mode.

As shown in FIG. 8B, during a cooling mode at full capacity the valve structure 830 will be set to allow the flow of refrigerant in the direction it flows during the cooling mode. During the cooling mode at full capacity the valve 170, 270 will allow the flow of refrigerant in the direction it passes during the cooling mode.

As shown in FIG. 8C, during a cooling mode at reduced capacity the valve structure 830 will be set to prohibit the flow of refrigerant in the direction it flows during the cooling mode. During the cooling mode at reduced capacity the valve 170, 270, 375, 475 will prohibit the flow of refrigerant in the direction it passes during the cooling mode.

Therefore, as shown in FIGS. 8B and 8C, the valve structure 830 can be selectively controlled to either pass cooled refrigerant in the direction it flows during a cooling mode or to prohibit the passage of cooled refrigerant in the direction it flows during a cooling mode. In this way the entire valve 170, 270, 375, 475 can be controlled to either pass or prohibit the passage of cooled refrigerant in the direction it flows during a cooling mode.

The valve structure of FIGS. 8A-8C can be used on either side of the air-conditioning coil 105. This is because the valve designs generally used for the valve structures 830 is of a size that functions well with both refrigerant in a gaseous state and refrigerant in a liquid state. As a result, the valve structure of FIGS. 8A-8C may be used for any of valves 170, 270, 375, and 475.

Method of Operation

FIG. 9 is a flow chart of a cooling operation 900 of an air-conditioning unit having an air-conditioning coil with a controllable capacity according to disclosed embodiments.

As shown in FIG. 9, the cooling operation 900 begins by stopping the flow of refrigerant through M first coil paths selected from N total coil paths that make up an air-conditioning coil. (910) The N total coil paths are arranged in parallel with respect to return air that passes through the air-conditioning coil such that any given portion of the return air passes over only one of the N total coil paths before it leaves the air-condition coil.

Operation continues by distributing cooled refrigerant only through P second coil paths selected from the N total coil paths that make up the air-conditioning coil and different from the M first coil paths. (920) The cooled refrigerant is cooled to a temperature sufficiently low that it will cause moisture to condense out of any air that passes over one of the P second coil paths containing the cooled refrigerant. In this case, P equals (N−M). In other words, the M first coil paths that have no cooled refrigerant passing through them and the P second coil paths having cooled refrigerant passing through them together make up the N coil paths that form the air-conditioning coil.

By distributing cooled refrigerant through the P second coil paths and not through the M first coil paths, the operation configures the air-conditioning coil such that air that passes over the P second coil paths will be both cooled and dehumidified, while air that passes over the M first coil paths will be neither cooled nor dehumidified.

Return air is then received at an input of the air-conditioning coil. (930) this air can be divided into N portions, each of the N portions being supplied to a corresponding one of the N coil paths such that any given one of the N portions of the return air passes over only one of the N coil paths as it travels through the air-conditioning coil.

M portions of the return air are passed over corresponding ones of the M first coil paths to generate M unconditioned portions of supply air, respectively. (940) Each of these M unconditioned portions of supply air are neither cooled nor dehumidified.

P portions of the return air are passed through corresponding ones of the P second coil paths to generate P conditioned portions of supply air. (950)

Each of these P conditioned portions of supply air are then cooled by exchanging heat between the P portions of the return air and the cooled refrigerant that passes through respective P second coil paths. (960) As the P portions of return air are cooled, they are also dehumidified by having moisture condense on respective P second coil paths from the P portions of supply air that respectively pass over the P second coil paths. This is because the cooled refrigerant passing through the P second coil paths is cold enough to cause moisture to condense from air that passes over one of the P second coil paths.

The P conditioned portions of the supply air are then combined with the M unconditioned portions of the supply air to form combined supply air. (970) Although the M unconditioned portions of the supply air have been neither cooled nor dehumidified, the P unconditioned portions of the supply air have been both cooled and dehumidified. As a result, the combined supply air will be both cooler and less humid than the return air was.

The combined supply air is then provided to a target zone that the air-conditioning unit services. (980) in this way, return air drawn from the target zone is both cooled and dehumidified by this cooling operation, even though the air-conditioning unit is operating at a reduced capacity compared to its full capacity.

CONCLUSION

This disclosure is intended to explain how to fashion and use various embodiments in accordance with the invention rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. The various circuits described above can be implemented in discrete circuits or integrated circuits, as desired by implementation. 

What is claimed:
 1. An air-conditioner unit, comprising: an input vent configured to receive return air; an output vent configured to pass supply air; an air-conditioning coil located between the input vent and the output vent and configured to receive the return air, pass the return air through the air-conditioning coil, and eject the supply air, the air-conditioning coil including a plurality of coil paths configured to pass refrigerant, the plurality of coil paths being configured to accommodate a flow of refrigerant; a refrigerant regulator connected to the plurality of coil paths and configured to regulate the flow of the refrigerant through the plurality of coil paths, wherein the refrigerant regulator is configured to have a least two selectable settings, the first selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator stops refrigerant from flowing through a first subset of the plurality of coil paths and allows refrigerant to flow through a second subset of the plurality of coil paths, the second selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator allows refrigerant to flow through all the plurality of coil paths, the plurality of coil paths in the air-conditioning coil are arranged in parallel with respect to a flow of return air through the air-conditioning coil such that any portion of return air will pass over only one of the plurality of coil paths as the return air flows through the air-conditioning coil from the input vent to the output vent.
 2. The air-conditioner unit of claim 1, wherein the refrigerant regulator further comprises a valve configured to selectively allow or stop refrigerant from flowing through the first subset of the coil paths.
 3. The air-conditioner unit of claim 2, wherein the valve is located on a side of the air-conditioning coil that is upstream of the refrigerant flow through the coil paths during a heating mode and is downstream of the refrigerant flow through the coil paths during a cooling mode.
 4. The air-conditioner unit of claim 2, wherein the valve is located on a side of the air-conditioning coil that is downstream of the refrigerant flow through the coil paths during a heating mode and is upstream of the refrigerant flow through the coil paths during a cooling mode.
 5. The air-conditioner unit of claim 1, wherein the refrigerant regulator further comprises a plurality of valves configured to selectively allow or stop refrigerant from flowing through the first subset of the coil paths, respectively, and each of the coil paths in the first subset of coil paths is associated with one of the plurality of valves.
 6. The air-conditioner unit of claim 5, wherein the plurality of valves are located on a side of the air-conditioning coil that is upstream of the refrigerant flow through the plurality of coil paths during a heating mode and is downstream of the refrigerant flow through the plurality of coil paths during a cooling mode.
 7. The air-conditioner unit of claim 5, wherein the plurality of valves are located on a side of the air-conditioning coil that is downstream of the refrigerant flow through the plurality of coil paths during a heating mode and is upstream of the refrigerant flow through the plurality of coil paths during a cooling mode.
 8. An air-conditioner unit, comprising: an input vent configured to receive return air; an output vent configured to pass supply air; an air-conditioning coil located between the input vent and the output vent and configured to receive the return air and eject the supply air, the air-conditioning coil including N separate coil paths configured to pass refrigerant, the N coil paths each having a first port and a second port; N first refrigerant lines corresponding to the N coil paths, each of the N first refrigerant lines being connected to the first port on a corresponding one of the N coil paths and being configured to pass refrigerant to or from the corresponding coil path; N second refrigerant lines corresponding to the N coil paths, each of the N second refrigerant lines being connected to a second port on a corresponding one of the N coil paths and being configured to pass the refrigerant to or from the corresponding coil path; and a refrigerant regulator connected to the N coil paths and configured to regulate the flow of the refrigerant through the N coil paths, wherein the refrigerant regulator is configured to have a least two selectable settings, the first selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator stops refrigerant from flowing through M first coil paths of the N coil paths and allows refrigerant to flow through P second coil paths of the N coil paths, the second selectable setting of the refrigerant regulator configures the refrigerant regulator such that the refrigerant regulator allows refrigerant to flow through all N coil paths, the air-conditioning coil is configured such that the return air will pass into the air-conditioning coil from the input vent, exchange heat with one of the N coil paths, and be ejected from the air-conditioning coil as the supply air, the N coil paths in the air-conditioning coil are arranged in parallel with respect to a flow of return air through the air-conditioning coil such that any portion of return air will pass over only one of the N coil paths as the return air flows through the air-conditioning coil from the input vent to the output vent, N is an integer greater than 1, M is an integer greater than 0, P=N−M, and M<N.
 9. The air-conditioner unit of claim 8, further comprising: a third refrigerant line configured to receive refrigerant from the N second refrigerant lines, wherein the N second refrigerant lines are connected to the third refrigerant line at N connection points, respectively, the refrigerant regulator further comprises a valve located in the third refrigerant line between M first connection points selected from the N connection points and P second connection points selected from the N connection points, and the valve is configured to selectively allow or stop refrigerant from flowing through the M first coil paths.
 10. The air-conditioner unit of claim 9, wherein the valve includes a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; and a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output opening to the input opening, and the one-way valve is oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.
 11. The air-conditioner unit of claim 9, wherein the valve is one of a bi-flow directional solenoid valve, a solenoid and check valve, a linear expansion valve, and a direct-acting solenoid valve.
 12. The air-conditioner unit of claim 8, further comprising: a third refrigerant line configured to receive refrigerant from the N second refrigerant lines, wherein the N second refrigerant lines are connected to the third refrigerant line at N connection points, respectively, and the refrigerant regulator further comprises M valves located in M second refrigerant lines, respectively, of the N second refrigerant lines between corresponding M first coil paths in the N coil paths and corresponding M first connection points of the N connection points, the M valves being configured to selectively allow or stop refrigerant from flowing through the M first coil paths, respectively.
 13. The air-conditioner unit of claim 12, wherein the M valves each include a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; and a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output opening to the input opening, and the one-way valve is oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.
 14. The air-conditioner unit of claim 8, further comprising: a refrigerant distributor having a first refrigerant path on a first end and N second refrigerant paths on a second end, wherein the N first refrigerant lines are connected to the N second refrigerant paths, respectively, and the refrigerant regulator further comprises M valves located in M first refrigerant lines, respectively, of the N first refrigerant lines between corresponding M first coil paths in the N coil paths and the corresponding M second refrigerant paths of the N second refrigerant paths, the M valves being configured to selectively allow or stop refrigerant from flowing through the M first coil paths, respectively.
 15. The air-conditioner unit of claim 14, wherein the M valves each include a main refrigerant path; a bypass refrigerant path connected to the main refrigerant path at a first path connection and a second path connection; a two-way valve having a first opening and a second opening, the two-way valve being located on the main refrigerant path between the first and second path connections, the two-way valve having an open position in which refrigerant can flow through the two-way valve from the first opening to the second opening and from the second opening to the first opening and a closed position in which refrigerant cannot flow through the two-way valve; and a one-way valve having an input opening and an output opening, the one-way valve allowing refrigerant to flow from the input opening to the output opening and preventing refrigerant from flowing from the output port to the input port, and the one-way valve is oriented such that the input opening is upstream of refrigerant flow during a heating mode and is downstream of the refrigerant flow during a cooling mode.
 16. The air-conditioner unit of claim 8, further comprising: a first refrigerant distributor configured to pass the refrigerant and having a first refrigerant path on a first end and M second refrigerant paths on a second end; a first expansion valve connected to the first refrigerant path and configured to controllably restrict a first flow of refrigerant through the first refrigerant path; a second refrigerant distributor configured to pass the refrigerant and having a third refrigerant path on a first end and P fourth refrigerant paths on a second end; and a second expansion valve connected to the third refrigerant path and configured to controllably restrict a second flow of refrigerant through the third refrigerant path, wherein M controllable first refrigerant lines selected from the N first refrigerant lines are connected to the M second refrigerant paths in the first refrigerant distributor, respectively, P non-controllable first refrigerant lines selected from the N first refrigerant lines are connected to the P fourth refrigerant paths in the second refrigerant distributor, respectively, and the refrigerant regulator comprises the first and second expansion valves.
 17. The air-conditioner unit of claim 8, further comprising: a refrigerant distributor configured to pass the refrigerant and having a first refrigerant path on a first end and N second refrigerant paths on a second end; an expansion valve connected to the first refrigerant path and configured to controllably restrict a flow of refrigerant through the first refrigerant path, wherein the N first refrigerant lines are connected to the N second refrigerant paths, respectively.
 18. A method of operating an air-conditioner in a cooling mode, the air-conditioner having an air-conditioning coil, the air-conditioning coil having N parallel coil paths, the method comprising: stopping refrigerant flow through M first coil paths selected from the N parallel coil paths; distributing refrigerant through P second coil paths selected from the N parallel coil paths; receiving return air at the air-conditioning coil; passing M first portions of the return air through the air-conditioning coil past the M first coil paths as M unconditioned portions of supply air, respectively; passing P second portions of the return air through the air-conditioning coil past the P second coil paths as P conditioned portions of supply air, respectively; cooling the P second portions of the return air by exchanging heat between the P second portions of the return air and the refrigerant distributed through the P second coil paths, respectively, to generate the P conditioned portions of supply air; and combining the M unconditioned portions of supply air and the P conditioned portions of supply air to form combined supply air, wherein each of the M first portions of return air and each of the P second portions of the return air flow past only one of the N parallel coil paths, N is an integer greater than 1, M is an integer greater than 0, P=N−M, and M<N.
 19. The method of claim 18, wherein the operation of stopping refrigerant flow through the M first coil paths further includes operating a single valve to stop the flow of refrigerant through the M first coil paths.
 20. The method of claim 18, wherein the operation of stopping refrigerant flow through the M first coil paths further includes operating M valves to stop the flow of refrigerant through the M first coil paths, respectively, and M is an integer greater than
 1. 